Topic 4: Fats & Oils Flashcards
why do we need fats and oils?
Fats are a source of essential fatty acids, our brain for instance is composed of roughly 60% fat, DHA is also another fatty acid accounting for 40% of polyunsaturated fatty acids in our brain and 60% in the retina of your eye.
What vitamins are soluble in fat?
Vitamin A, D, E, K (helps with Blood clotting, and loncardiovascular health)
What is the function of fats and oils in cooking?
flavor preservation, creamy texture in sauces, varrying textures when cooking with oil, glossy/moist appearance, use in emulsions, satiety, efficient mode of heat transfer
What are fats and oils chemically?
long organic acids, fatty acids, 1 glycerol molecule + 3 fatty acid molecules react and make fats called triglycerides + water
fat molecules atoms and composition?
chain of 3 fatty acid –>6 oxygen atoms, can have 50 carbons and over 100 hydrogens. mostly just carbon (C) and hydrogen (H)
what are the types of diagrams to display the fat molecules?
structural formula, ball and stick model, space-filling model, bond line formula
saturated vs unsaturated?
Saturated: saturated with hydrogen, an entire chain of single bonds between carbon atoms. higher melting point, solid, common in meat
unsaturated: have double bonds, lower melting point and more likely a liquid, common in plants
Example of a mono-unsaturated fatty acid
oleic acid (only has one double bond)
*Monounsaturated fat consumption has been associated with decreased low-density lipoprotein (LDL) cholesterol
what is poly unsaturated fatty acid?
unsaturated fatty acid with at least 2 or more double bonds eg. (α-linolenic acid) Three double bonds,
common omega-3 fatty acids?
docosahexaenoic acid (DHA) ,
eicosapentaenoic acid (EPA), —> found in cold water fish, ie tuna, salmon, sardine
α-linolenic acid (ALA)–> found in plant sources canola oil, walnuts, flaxseed, and soybean
omega 3 and omega 6 fatty acids are….
Polyunsaturated fatty acids also ‘essential fatty acids’ because the human body cannot synthesize it.
omega-3 fatty acids are?
fatty acids have a double bond three carbons away from the methyl carbon.
What is the ideal intake ratio of omega-3 to omega-6
1:1-4
Omega-6 fatty acids are?
polyunsaturated fatty acids that have a final carbon-carbon double bond in the sixth bond, counting from the methyl end.
omega-3 decreases this but omega 6 contribute to
risk for heart disease & cancer, has anti-inflammatory properties the later contributes to inflammation
All fats are different percentages of…
saturated, polyunsaturated or monounsaturated.
trans fatty acids?
a type of unsaturated fat in processed foods, trying to make it more saturated. They use the process of hydrogenation reaction where the structure of the molecule chaces from cis to trans.
is unsaturated or saturated fat better for cooking
unsaturated fat is said to promote more health benefits whilst saturated fats increases the risk of heart disease,
What are some oil-based cooking methods
deep-fry, pan fry, confit, sauteing, stir fry
What is confit?
slow cooking low heat in oil method at 90 C
Maillard Reaction?
reaction between amino acids and reducing sugars creating aromatic compounds (reaction proceeds from around 140 °C)
Caramelization
a reaction between sugar molecules, this results in nutty flavor and brown color. Sucrose breaks down into and glucose and fructose and caramelize around 170 °C. As the process occurs, volatile chemicals are released producing the characteristic caramel flavor.
Thiopenes?
sulfur containing compounds with meaty quality
oxazoles?
oxygen-containing compound with nutty sweet taste
alapyridaine?
a maillard reaction product that enhances the flavor of meatiness, sweetness and saltiness
reducing sugars?
the sugar compound gives some of their electrons to other molecules
what are fructose and glucose examples of?
reducing sugars
what flavor does diacetyl produce?
buttery flavor
what flavor does furan give?
nutty flavor
what flavor does acetaldehyde produce?
rum flavor
explain the caramelization and maillard reaction that takes place when cooking onions
carbohydrates (sugar molecules) in the onion break down when heat is added. The carbonyl group start to bind with the amino groups from amino acids
caramelization is thermogenic in nature
what does thermogenic mean?
produces heat as it reacts
who was Ancel Keys?
he was responsible for inciting fear over saturated fat. Correlating fat consumption as the reason for high cholesterol and heart diseases
what were the benefits of a high fat, low carb diet?
though many had presumed that fat was causing heart diseases, it was in fact carbohydrates (sugars) that were what worsened triglyceride concentration (the main cause) in the blood stream. To decrease that concentration, a high fat, low carb was what actually helped.
